Triphenylboron-pyridine is known to be an effective biocide for a variety of applications, particularly in commercially valuable marine anti-fouling coatings. See, for example, U.S. Pat. No. 3,211,679, U.S. Patent Publication No. 2007/0299259, U.S. Pat. No. 7,045,560 and JP 08-052908 (all four being incorporated herein by reference).
Such solvent-based anti-fouling coatings generally contain xylene or similar aromatic solvents, utilize a variety of acrylate resin systems to form the basis of the coating, and contain one or more biocides, such as TPBP, which preferably should remain active and stable for extended periods of storage, particularly at elevated temperatures. There is some indication in published literature that under certain conditions TPBP may generate low levels of benzene. For example, in The Handbook of Environmental Chemistry, Hutzinger, Editor-in-Chief, Vol. 5, loannis K. Konstantinou, Volume Editor, Antifouling Paint Biocides, pp. 194-195, Springer-Verlag, Berlin, Heidelberg, 2005, states that the photodegradation of TPBP was studied by Amey and Waldron in aerated artificial seawater, using UV irradiation. The photodegradation of TPBP and primary intermediate photoproducts of mono- and di-phenylboron acids was rapid. The secondary by-products, pyridine, phenol, and benzene were also observed.
Nasvadba et al., U.S. Patent Publication No. 2007/0225397, proposes the use of stable, highly sterically hindered nitroxyl radicals, defined by the specific formulae, as in-can stabilizers for UV-curable resins. The term “highly sterically hindered” is defined to mean that ring nitroxyl radicals of the formulas are more hindered than ring nitroxyl radicals having 4 methyl groups in the alpha position to the N-atom, for example more hindered than TEMPO (2,2,6,6-tetra-methylpiperidinyl-1-oxy-radical). Nasvadba et al. also state that WO01/42313 proposes the use of sterically hindered nitroxyl radicals, such as TEMPO, for stabilization of UV-curable resins.
Warnez, U.S. Pat. No. 4,303,444, proposed a method for inhibiting benzene formation in resin-based anti-fouling paints, by adding trialkyl tin oxide or hydroxide to the paints.